Method and apparatus for removing suspended material from underground mine water

ABSTRACT

An apparatus and method is provided for continuously removing undesirable suspended material from a continuous stream of underground mine water by thermally decomposing the material to a residue and passing the residue back into the moving stream of underground mine water.

United States Patent Inventor Frank E. Ralph Butte, Mont.

Appl. No. 6,247

Filed Jan. 27, 1970 Patented Dec. 28, 1971 Assignee The Anaconda Company New York, N.Y.

METHOD AND APPARATUS FOR REMOVING SUSPENDED MATERIAL FROM UNDERGROUND MINE WATER 7 Claims, 3 Drawing Figs.

U.S. C1 210/67, 210/152, 210/179 Int. Cl B0ld 37/00 Field 01 Search 210/63, 67,

[56] References Cited UNITED STATES PATENTS 1,301,532 4/1919 Allen 210/67 X 1,329,727 2/1920 Smith 210/152 X 3,486,621 12/1969 Hirs 210/152X Primary Examiner-Samih N. Zahama Attorney-Pennie, Edmonds, Morton, Taylor and Adams ABSTRACT: An apparatus and method is provided fgfcontinuously removing undesirable suspended material from a continuous stream of underground mine water b'y thermally decomposing the material to a residue and passing the residue back into the moving stream of underground mine water.

PATENTEU UEE28 ism SHEET 1 [IF 2 1 i METHOD AND APPARATUS FOR REMOVING SUSPENDED MATERIAL FROM UNDERGROUND MINE WATER BACKGROUND OF THE INVENTION In underground mining operations it has about always been necessary to remove water continually from underground mine workings. Often this involves pumping the mine water from underground to the surface for further discharge into surface streams. Due to the physical nature of the mine water, problems are encountered in pumping it to the surface and dispersing it. Mine water is found to contain organic particulate material or fungus suspended therein. This particulate material or fungus, in the form of a fibrous substance, is undesirable since its presence clogs the pumping equipment used to raise the mine water to the surface and is found to pollute the surface streams.

Various methods have been devised to eliminate such organic material from the mine water. One such method includes manually positioning a portable rectangular screen across an underground mine water drainage stream, collecting the suspended material on the screen, manually removing the screen from the mine water stream, scraping the collected suspended material from the screen and reimmersing the cleaned screen back into the stream for further collection of the organic material. This technique, while it satisfactorily removes the suspended materials from the mine water, requires the constant manual attention and supervision of an operator.

Another method used to remove the undesirable suspended material from the mine water involves the incorporation of various additives into the mine water in order to dissolve or chemically decompose the suspended material. While such additives have been found to satisfactorily dissolve the suspended material and eliminate the pump clogging problem, the additives have undesirably changed the chemical nature of the mine water in such a way to thereby render it unsuitable for use, for example as a leaching acid in subsequent dump leaching operations or for disposal into surface streams.

SUMMARY OF THE INVENTION This invention relates to a method and apparatus for freeing a stream of mine water from thermally decomposable suspended organic material which comprises passing the stream through an endless traveling screen extending across the stream, collecting the material on the screen, advancing the screen with the material that collects thereon to the open air above the screen, thermally decomposing the material to a mainly inorganic residue by heating the material collected on the screen at a point when the screen is above the stream, and passing the residue back into the moving stream of mine water by returning the screen bearing such residue to a position extending across the stream.

In accordance with the techniques of this invention, underground mine water may be effectively and economically conditioned to remove undesirable suspended material so that the mine water may be transported to the surface and further used in subsequent dump leaching operations or for dispersal into surface streams.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view ofthe invention; FIG. 2 is a side view of the invention; and FIG. 3 is a sectional view taken along line 3-3 of FIG. 2.

DESCRIPTION OF THE INVENTION Referring now to the drawings, the invention comprises an apparatus, generally indicated by l, which is supported to extend into a channel 2 along which an underground stream of mine water flows in the direction indicated by arrow A, shown in FIGS. 1 and 2. The apparatus includes a pair of base members 3 anchored to the sides of the channel 2. Each base members 3 is adapted to support therebetween a support frame 4 which is mounted in an inclined direction to partially extend into the stream of mine water.

The bottom ends of each support frame 4 carries therebetween a horizontal and elongated bottom roller 5 which is rotatably fixed to each support frame 4 by lower brackets 6.

The upper ends of each support frame 4 support a horizontal and elongated drive roller 7 which is rotatably fixed to the support frames 4 by upper brackets 8. The drive roller 7 is rotated by a motor 10 through an intermediate drive chain ll.

A side support 12 is adjustably fixed to each support frame 4 by means ofa tension screw 13 extending through a slot 14 in each of the support frames 4. Each side support 12 extends upwardly from each support frame 4 and rotatably secures a horizontally arranged, elongated tension roller 15 therebetween. The position of the tension roller 15 may be adjusted in a direction perpendicular to the support frames 12 merely by loosing the tension screw 13 and moving the tension roller 15 towards or away from the support frames 4.

An endless traveling screen 16, whose width is substantially equal to the width of the channel 2, is provided to extend and rotate about the bottom roller 5, drive roller 7 and tension roller 15.

A plurality of heating elements 17, preferably electric, are mounted to extend above base members 3 and across the channel 2 by brackets 18. The heating elements 17 also are so positioned to extend between the tension roller 15 and the drive roller 7 and immediately above that area of the traveling screen 16 moving between the tension roller 15 and the drive roller 7 in order to project heat against the outer surface of the traveling screen 16 in the aforementioned area.

An elongated sprayer 18 is mounted between each support frame 4 adjacent the drive roller 7 to extend across the width of the traveling screen 16. The sprayer 18, which may be connected to a fluid pressure source (not shown), such as water, steam or air, is so positioned to spray a fluid under pressure downwardly against and across the inside surface of traveling screen 16.

In the preferred arrangement, the bottom roller 5 is situated near the bottom of the channel 2 while drive roller 7 and tension roller 15 extend above the surface of the mine water. Accordingly, the surface area of the traveling screen 16 moving between the bottom roller 5 and both the tension roller 15 and the drive roller 7 is partially emersed in the mine water while the surface area of the traveling screen 16 moving between the tension roller 15 and the drive roller 7 is completely above the surface of the mine water. There is no criticality in the amount of surface area of the traveling screen 16 that should be submerged in the mine water except that the portion of the surface area of the traveling screen 16 receiving the fluid from the sprayer 18 should be above the level of the mine water to insure effective removal of any accumulated material from its surface.

In operation the traveling screen 16 is moved slowly in the direction indicated by arrow B, shown in FIGS. 1 and 2. As the traveling screen 16 moves through the mine water, the undesirably suspended organic material present in the flowing stream of mine water contacts the traveling screen 16 and is continuously collected on the outside surface thereof as the material is moved by the stream of mine water against the outside surface of the traveling screen 16. Upon further movement or advancement of the traveling screen 16, it emerges with the organic material collected thereon from the stream of mine water to the open air above the stream and is heated by the heating elements 17 until the suspended material is thermally decomposed to an inorganic residue which may simply fall from the traveling screen 16, return together with the traveling screen 16 to be washed clear of the traveling screen by the movement of the mine water against the inside surface thereof, or be forced or dislodge from the traveling screen 16 as the screen is returned toward the stream by the fluid under pressure acting against its inside surface of the screen 16 by the sprayer 18. In this arrangement it will be noticed that the residue, upon leaving the traveling screen 16, is directed back into the flowing stream of mine water and allowed to be carried away by the moving stream of mine water.

The particular mesh of the traveling screen 16 is not critical except that it must be of a size small enough to collect the suspended material thereon and thus effectively remove it from the mine water.

Having best described the invention with particular reference to the preferred forms thereof, it will be obvious to those skilled in the art to which this invention pertains, after understanding the invention, that various changes and modifications may be made therein without departing from the spirit and scope of the invention, as defined in the claims appended hereto.

lclaim:

l. The method of freeing a stream of mine water from thermally decomposable suspended organic material which comprises passing the stream through an endless traveling screen extending across the stream, collecting the material on the screen, advancing the screen with the material that collects thereon to the open air above the stream, thermally decomposing the material to a mainly inorganic residue by heating the material collected on the screen at a point when the screen is above the stream, and passing the residue back into the moving stream of mine water by returning the screen bearing such residue to a position extending across the stream.

2. The method of claim 1 including directing a fluid under pressure against the screen is returned toward the stream to dislodge the residue from the screen.

3. The method of freeing a moving stream of mine water from thermally decomposable suspended organic material which comprises collecting the material on the outside surface of an endless screen as the material is moved by the stream of mine water against the outside surface of the screen, advancing the screen and material that collects thereon to the open air above the stream, thermally decomposing the material to mainly an inorganic residue by heating the material collected on the screen at a point when the screen is above the stream, dropping the residue from the screen into the moving stream of mine water to be carried away from the screen by the moving stream of mine water and washing any remaining residue from the outside surface of the screen by movement of the stream of mine water against the inside surface of the screen to allow the residue to also be carried away by the moving stream of mine water.

4. The method of claim 3 including directing a fluid under pressure against the insidesurface of the screen as the screen is returned toward the stream to dislodge the residue from the screen.

5. In an apparatus for continuously removing thermally decomposable material from a stream of mine water including an endless traveling screen, said screen being constructed and arranged so that the lower portion thereof extends into the stream for collecting the material while the upper portion thereof extends above the stream, a heater situated adjacent the upper portion of the screen above the stream in position to thermally decompose to a residue the material collected on the screen and carried thereby above the stream, and means for advancing the screen out of the stream and passing it back together with the residue into the stream of mine water.

6. The apparatus of claim 5 including means to remove the residue from the screen including a fluid pressure sprayer positioned above the stream and adjacent the screen.

7. The apparatus of claim 5 wherein said sprayer directs fluid under pressure against the inside surface of the endless traveling screen to wash the residue from the screen. 

2. The method of claim 1 including directing a fluid under pressure against the screen is returned toward the stream to dislodge the residue from the screen.
 3. The method of freeing a moving stream of mine water from thermally decomposable suspended organic material which comprises collecting the material on the outside surface of an endless screen as the material is moved by the stream of mine water against the outside surface of the screen, advancing the screen and material that collects thereon to the open air above the stream, thermally decomposing the material to mainly an inorganic residue by heating the material collected on the screen at a point when the screen is above the stream, dropping the residue from the screen into the moving stream of mine water to be carried away from the screen by the moving stream of mine water and washing any remaining residue from the outside surface of the screen by movement of the stream of mine water against the inside surface of the screen to allow the residue to also be carried away by the moving stream of mine water.
 4. The method of claim 3 including directing a fluid under pressure against the inside surface of the screen as the screen is returned toward the stream to dislodge the residue from the screen.
 5. In an apparatus for continuously removing thermally decomposable material from a stream of mine water including an endless traveling screen, said screen being constructed and arranged so that the lower portion thereof extends into the stream for collecting the material while the upper portion thereof extends above the stream, a heater situated adjacent the upper portion of the screen above the stream in position to thermally decompose to a residue the material collected on the screen and carried thereby above the stream, and means for advancing the screen out of the stream and passing it back together with the residue into the stream of mine water.
 6. The appaRatus of claim 5 including means to remove the residue from the screen including a fluid pressure sprayer positioned above the stream and adjacent the screen.
 7. The apparatus of claim 5 wherein said sprayer directs fluid under pressure against the inside surface of the endless traveling screen to wash the residue from the screen. 